Fix following in other version of article

src/main/resources/sql/functions/follow/find_follow.sql

@@ -1,22 +1,43 @@
 create or replace function find_follow(
     _target_id uuid,
     _citizen_id uuid,
+    _target_reference regclass,
     out resource json,
     out following boolean
 ) language plpgsql as
 $$
+declare
+    _target_ids uuid[];
 begin
-    select to_json(t)
-    into resource
-    from (
-        select
-            f.*,
-            json_build_object('id', f.target_id, 'reference', f.target_reference) as target,
-            find_citizen_by_id(f.created_by_id) as created_by
-        from follow as f
-        where f.created_by_id = _citizen_id
-          and f.target_id = _target_id
-    ) as t;
+    if (_target_reference = 'article'::regclass) then
+        select array_agg(a2.id) into _target_ids
+        from article a1
+        join article a2 using (version_id)
+        where a1.id = _target_id;
+
+        select to_json(t) into resource from (
+            select
+                f.*,
+                json_build_object('id', f.target_id, 'reference', f.target_reference) as target,
+                find_citizen_by_id(f.created_by_id) as created_by
+            from follow as f
+            where f.created_by_id = _citizen_id
+              and array[f.target_id] <@ _target_ids
+            limit 1
+        ) as t;
+    else
+        select to_json(t)
+        into resource
+        from (
+            select
+                f.*,
+                json_build_object('id', f.target_id, 'reference', f.target_reference) as target,
+                find_citizen_by_id(f.created_by_id) as created_by
+            from follow as f
+            where f.created_by_id = _citizen_id
+              and f.target_id = _target_id
+        ) as t;
+    end if;
 
     select resource is not null into following;
 end;